The Structure and Special Physiology of Insects 21 



in the paired arrangement of the spiracles and tracheal trunks leading from 

 them, a segmental condition is obvious. The central nervous system consists 



Fig. 41. — Larva of giant crane-fly, Holorusia ruhiginosa. A, entire; B, dissected, show- 

 ing all organs except the muscles and ventral nerve-chain. /;., head; ant., antenna; 

 i.b.rcs., imaginal bud of pupal respirator}' tube; i.b.wg., imaginal bud of wing; 

 i.b.ms.l., imaginal bud of mesothoracic leg; i.b.h., imaginal bud of balancer; 

 i.b.mt.!., imaginal bud of metathoracic leg (the imaginal buds of fore legs are con- 

 cealed by head-capsule); sal.gl., salivary gland (the other salivary gland is removed); 

 br., brain; <es., oesophagus; prov., proventriculus; stisp., suspensorium; g.c, gastric 

 ccecum; vent., ventriculus; tr., trachea; ad. lis., adipose tissue; mal.tub., Malpi- 

 ghian tubule; d.v., dorsal vessel; -.cm., wing-muscles of pericardium; sm.iiit., 

 small intestine; les., testis; int.c, intestinal caecum; v.d., vas deferens; Lint., large 

 intestine; sp., spiracle; term.pr., terminal processes. (Twice natural size.) 



of a brain and a ventral chain of pairs of ganglia segmentally arranged and 

 connected by a pair of longitudinal cords or commissures (Figs. 42, 43, 44). 

 The two members of each of the pairs of ganglia as well as of the pair of 



